Network Interface Virtualization Using FEX

Cisco FEX technology is based on the IEEE 802.1BR standard. The Cisco FEX technology solution is composed of a parent switch that can be a Cisco Nexus 5000 Series switch, Nexus 6000 Series switch, Nexus 7000 Series switch, Nexus 9000 Series switch, or a Cisco UCS fabric interconnect. The parent switch is then extended to connect to the server either as a remote line card with Nexus 2000 Series fabric extenders or logically partitioned or virtualized adapter ports to connect to any type of servers (racks and/or blades), with Cisco Adapter FEX and VM-FEX technologies. FEX technology has been discussed in detail in Chapter 2, “Describing the Cisco Nexus Family and Cisco NX-OS Software.” Here, we will discuss the network adapter virtualization using adapter FEX and VM-FEX technology.

• Cisco Adapter FEX: Typical deployments of virtual machines have an extra layer of switching in the hypervisor. The software switches in the hypervisor emulate hardware at the expense of application performance. Cisco virtual interface cards (VICs) solve this problem by acting as adapter fabric extenders and bringing the network to virtual machines (VMs) using Cisco Adapter FEX technology. Cisco Adapter FEX enables the server adapter to be logically partitioned into multiple virtual network interface cards (vNICs). Each vNIC behaves like a physical NIC port and meets the network connectivity needs for each application so that security and quality of service (QoS) policies can be applied for each vNIC and application.
• Cisco Data Center VM-FEX: Network administrators have no control on the software switches in the hypervisor, which makes monitoring of network traffic to individual VMs very cumbersome. Cisco VICs use the VN-Tag standard in IEEE 802.1 BR standard to manage each link from the VM as if it were a physical link. The VICs can provide dynamic interfaces to virtual machines, allowing the network to bypass the hypervisor and directly connect to the VM using VM-FEX technology. Cisco Data Center VM-FEX partitions the server adapter into multiple vNICs, and each vNIC is assigned to individual virtual machines, allowing network administrators to monitor the ports easily. Additionally, the VMs can move from one server to another with the same security policies and no compromises on the overall network security to allow the move. Switching of VM traffic happens in hardware switches instead of using a software switch within the hypervisor.

Figure 7-20 illustrates the difference in the implementation of Adapter FEX and VM-FEX technology using Cisco VIC card.

   

Figure 7-20 Adapter FEX vs VM-FEX

VMware vSphere Virtual Switches

Virtual switches are the key networking components in the VMware infrastructure. VMware vSphere virtual switches provide network connectivity to hosts and virtual machines and support VLANs that are compatible with standard VLAN implementations.